The present invention is related to radio frequency (RF) communication technology, and more particularly to a digital demodulator for use in a frequency modulation (FM) receiver.
In communication devices, such as RF receiver or transceiver devices, modulated RF signals are received and demodulated in order to extract the information carried by the RF signal. FM is one type of modulation widely used in cellular and paging systems. The FM signal is demodulated by a demodulator in the receiver device.
A conventional analog demodulator is most commonly used in FM receivers. An analog demodulator includes a post detection filter to eliminate unwanted signal frequencies generated as a result of the demodulation process. It is desirable to eliminate the need for the post detection filter, particularly when the information to be recovered as a result of the demodulation is digital data. It is also desirable to realize a digital demodulator which operates at an optimally low clock frequency, thus maximizing system power efficiency.
An all digital demodulator is needed that eliminates all of the drawbacks associated with an analog demodulator and which can efficiently be implemented in an integrated circuit environment.